<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>赋值判等</title>
</head>
<body>
    
</body>
<script>
    //=赋值    ==判等        ===判类型和字面值相等
    //发反写，字面量在前，变量在后（防止出现 = 判等）
     var a = 45;
     var b = "45";
     console.log(a===b);
    if(45==a)
    {
        console.log("相等");
    }
    //对像判等  是比较地址
    //NaN===NaN  输出false
    //！==   是 ===的逆运算

</script>
</html>